Ultrasonographic measurement of the collateral ligaments of the distal interphalangeal joint in the Argentine Polo Horse.

The collateral ligaments of the distal interphalangeal joint (CL-DIPJ) are important structures for athletic horses. Ligament injuries can cause lameness, but ultrasound imaging can detect such lesions, which usually present with changes in echogenicity and an increase in the cross-sectional area (CSA) of the ligament. Measurements of these structures vary among authors, which complicates the diagnosis. Thus, this study aimed to describe the ultrasound measurements (dorsopalmar diameter [DPD], lateromedial diameter [LMD], and CSA) of the CL-DIPJ in Argentine Polo horses. We measured the CL-DIPJ of 25 Argentine Polo horses. The measurements were repeated three times, and the mean value for the selected variables was calculated. The Student's t-test was applied to compare the contralateral ligaments and, subsequently, the lateral (LCL) and medial (MCL) collateral ligaments, regardless of the thoracic limb assessed. There was no difference (p> 0.05) between the contralateral ligaments. Similarly, no difference was found between the LCL and MCL for DPD and LMD. Regarding the CSA, there was a difference (p < 0.05). Thus, the mean values for the CL-DIPJ of the thoracic limbs of Argentine Polo horses were 13.13 ± 0.83 mm for the DPD, 8.79 ± 0.57 mm for the LMD, and a cross-sectional area of 0.97 ± 0.06 cm2 for the LCL and 0.98 ± 0.05 cm2 for the MCL.